Automatic film-tensioning mechanism



July 26, 1927.

1,636,954 f F. E. GARBUTT AUTOMATIC FILM TENSIONING MECHANISM Filed March 2, 1966 3 Sheets-Sheet l 1g 1,636,954 July 26 27 F. E. GARBUTT AUTOMATIC FILM TENSIONING MECHANISM Fliled March 2, 1926 3 Sheets-Sheet 2 r N r V m @E MM5 1 mm mg ma @fw/ m M f gf &\ Q :Q f rml Q Q o O o @f l Em mom \QM\ www s NQ www @mi o \m\ N WSN n /f @su /m @um @u MQ w@ mmm- NSM .www SWW/mm v mm QMWQM 1 MMM \\NM %h\\ 1,636,954 July 26 1927 F. E. GARBUTTv AUTOMATIC FILM TENSIONING MECHANISM Filed March 2, 1926 3 Sheets-Sheet 3 LA Ll il ,Lgf E my y n 1 Qi l ff/1min g Elli g S@ an,

Patented July 26, 1927.

PATENT OFFICE.

FRANK E. GABBUTT, F LUS ANGELES, CALIFORNIA.

AUTOMATIC FILM-TENSIONING MECHANISM.

Application led Karel: 2, 1928. Serial No. 91,697.

This invention relates to the art of developing photographic film, and it relates particularly to an automatic machine especilally adapted for developing motion picture fi m.

Both positive and negative films, after their exposure, are subjected to a series of consecutive treatments which prepare the1nfor use. Film generally passes through the following steps: the development of the images by immersing the film in adevelolping solution; the fixation of the images y immersion of the film in fixative solutions;

washing the film to remove all adhering solutions; dyeing and toning thefilm for emphasizing the images; and finally drying the film. Motion picture film is carried through these treatments either manually or by automatic machines.

In carrying out the above treatments manually, the exposed film is wrapped on racks and immersed in the various solutions. After this, the film is removed from the racks and wound on rotating drums for drying. The film must be watched very closely so that they will be subjected to various solutions for a proper length of time. This re uires the constant attention of workmen.- he handling of these films and the time taken to pass them through these treatments make the developing thereof comparatively expensive. There are at the present time automatic machines for developing film. These mashines comprise various solution tanks and drying compartments. In these tanks and drying compartments are series of rollers over which-the film is wound. The film is fed into one end of the machine, assin through the various solutions and t roug the dryer, and emerges from the opposite end of the machine completel developed and dried, and is ready for the cuttin room. The development of film by machine as been found `to be much more desirable than the old manual method of developin owing to the fact that the film may be veloped much quicker and much cheaper. The extenslve use of these automatic machines, however, has been restrained d ue to difficult be' encountered asa result of stretch an sh e of the film from a normal condition. When tions,

the film passes through the various soluit has been found empirically that the film will stretch from one-fourth to threeeighths of an inch in fifty feet, and it has also been found at other points in the develop ing machine that the film will shrink onefourth to three-eighths of an inch from normal. A shrinkage of the film places an excessive tension thereon and sometimes breaks it, and .when the film stretches it has been common for it to run off the rollers, thus causing considerable delay and is sometimes very expensive due to the fact that very i1nportant scenes are sometimes ruined, which, 35 if ruined on the negative, must be photographed again.

It is an object of my invention to provide an automatic film develo ing machine having means for automatically maintaining the film at a normal tension.

It is another object of my invention to provide in an automatic film developing machine of this character, an automatic tensioning means which retards and accelerates the film to either side of a place where an abnormal tension in the film exists. I provide my invention' in the form of a plurality of series of rollers. Each series of rollers comprises an upper roller and a lower roller. is consecutively wound over successive rollers. Gn one roller of each series of rollers I provide an arrangement whereby this roller may be retarded or accelerated in speed. This means is adapted to be operated by the film, when an abnormal tension exists, in such a manner as to readjust this i tension to normal.

It is another object of my invention to .provide in an automatic film developing machine an automatic tensioning arrangement which is actuated by a lower roller of said series of rollers. I accomplish this object v by providing lower rollers which are floating and are supported by the film itself. These rollers are connected with the retarding and accelerating arrangement or tensioning mechanism in such a manner that an abnormal tension in the film may be readjusted. When the tension in the film increases above normal, the floating or lower rollers are raised, and when the tension in the The film 80 film decreases below normal, the floating rollers are lowered.

In my arrangement the raising of one of the floating rollersl actuates the tensioning mechanism 'on a preceding series of rollers in such a manner as to retard the exhausting of the film to rthis series of rollers in which the floating roller has been raised. This retardation gives more film to this series and reduces the tension of the film, thus allowing the floating roller t0 return to a normal position. lVhenthe floating roller lowers below a normal position due to the decrease in tension of the film, a tensioning arrangement is operated in such a manner as to operate a preceding series of rollers in such a manner as to increase the feeding of the film to this series of rollers in which the floating roller has lowered, thus allowing the film to feed to this roller faster than it is exhausted therefrom and rectifying the variation in tension.V The floating roller will then return to a normal position, and the tensioningarrangement will also return/to normal position until such a time that the tension in the film againfbecomes abnormal.

It is another object of my vinvention to provide in an automatic film developing machine a means for automatically maintaining thelilml at a normal tension which is operated directly from the film. I accomlso plish this object by providing a multiplicity of series' of rollers, each of said series comprising upper and lower rollers. These rollers are permanently located in certain positions and alternate series of rollers are provided lwith brakes by which the rotational speedv thereof vmay be retarded when the brakes are applied. A tensioning lever is provided for eachseries of rollers having brakes, each of these tensioning levers being actuably connected with a brake of a series of rollers directly therebelow and a brake o a following series of rollers. The film` is wound over each series of rollers and in pass- 1n ovrY a roller secured to the end of a tensioning lever. When the film is passing over. the rollers, the tensioning levers rest in positions dependent upon the tension existing in the film. When the tension in the film increases, the tensioning levers are pulled downwardly, and when the tension in the film decreases, the tensioning levers move upwardly. A downward movement of the tensioning lever causes an application of one of the brakes associated therewith and a releasing of the other brakes associated therewith in such a manner that the abnormal tension in the lm will be rectified. When the tension in the lm decreases and the lever moves' upwardly, the brakes associated therewith are oppositely operated, and the abnormal tension is rectified.

Other objects and the salient advantages from one series to the next is extended of my invention will be made evident hereinafter.

Referring to the six sheets of drawings,

Fig. y1 is a `diagramma-tic view of a complete film developing apparatus embodying the features of the invention.

Fig. 2 is a fragmentary side view showing the details of the invention.

Fig. 3 is a section taken as indicated by the arrow 3 of,Fig. 2.

Fig. 4 is a plan view of Figs. 2 and-3.

With reference to these figures and -particularly to Fig. 1, the machine comprises tensioning mechanism 20 which is arranged to operate on a multiplicity of series of rollers 21. These ,rollers 21 are all supported by frames 22. In Fig. 1 I illustrate solution tanks 23 and 24 and a film dryer 26. The solution tanks 23 and 24 are supported from the floor by suitable beams 27. Extending upwardly from each side of the tanks 23 and 24 are columns 28. The frames 22 of the tanks 23 and 24 have slide formations 29 which surround the columns 28. A jack 30 from which a rodv31 extends is provided for elevating the frames 22 of the tanks 23 and v24 to permit threading of the film therearound. The exposed film to be developed is placed on a reel 33 supported by a bracket 34. The film 35 is threaded around rollers 36 su ported from one of the columns 28, and rom thence passes over the series of rollers 21 of the tank 23. From the rollers 21 of the tank 23 the film 35 is extended over rollers 38 supported by a column 28 of the tank 24, and from thence is wound over the series of rollers 21 of the tank 24. The film then passes overa ro1ler 40 and is wound on the series of rollers 21 in the dryer 26. From the dryer 26 the film 35 extends over a roller 41 and is finally wound on a reel 42. When the film passes from the dryer 26, it

:E has been completely developed and dried,

and is ready for the cutting room. A motor 43 is provided for driving the various sets of rollers. The motor 43 drives a shaft 44 which has a gear box 45 by which a shaft of the rollers 1n the dryer 26 is rotated. At the lower end of the shaft 44 a gear box 46 is provided which drives a shaft 47 of the frame 22 of the solution tank 24 by means of a. coupling 48. A shaft 49 of the frame 22 of the solution tank 23 is driven from the shaft 47 by acoupling 50. When either of the frames 22 in` the solution tanks .23 and 24 is elevated, it is necessary to detach the members of the couplings 48 or 50.

As shown in Figures 2, 3 and 4, this form of my invention has housings 150 which are supported by bars 151 extending therethrough. A driving shaft 152 passes through each of the housings 150 and has a gear 153 situated in each of the housings 150. The gears 153 mesh with gears 154 secured on members 155. each member 155 174 of each o'f the Shafts 157. This being rotatable on ashaft 157, Shafts 157 are retained in bearings 158 and 159 supportedVv in each of the housings 150. A ratchet wheel 161 is rigidly secured on each of the shafts 157 inside the housings 150. A pawl 162 is carried by each of the members 155, this pawl being adapted to engage the ratchet wheel 161, thus transferring rotation from the member 155 to the ratchet wheel 161. Each of the members 155 is rotated due to the engagement'between the gears 153 and 154. i

Upper rollers 165 are carried on the shafts 157. These rollers 165 have bushings 166 ateach end thereof which are pressed into counterbores 167. A friction plate 168'is secured to each of the shafts 157 adjacent to the housing 150. On the squared ends 169 of the shafts 157 outer friction plates 171 are arranged, these friction plates being forced into engagement with the outer bushings 166 bv compression springs 172, each of which is compressed by means of a wheel 173 which threads on a threaded end ressure of the outer friction plate 171 agiiinst each of the rollers 165 frictionally retains each of the rollers -165 between friction. plates 168 and 171, thus frictionally retainingl the rollers on the shafts 157. A support 176 extends from each of the housings 150 directly below a roller 165. Lower roller supports 177 extend downwardly from the supports 17 6 having blocks 178 situated at the lower ends thereof. VThe blocks 17 8 carry lower roller shafts 179 on which lower rollers180 are arranged. The upper rollers are provided with brake drums 183 at the left ends thereof, and the remainder of the roller is divided into spools 184 by walls 185 provided thereon. The lower rollers 180 are divided into spools 187 by walls 188 as shown clearly in Figs. 12 and 13. An upper roller 165 and a lower roller 180 cooperate to form a series of rollers.

In Fig. 2 I show a number of series of rollers 189, 19o, 191, 192, 193 and 194. on

alternate upper rollers 165 Iprovide inner.

and outer brake shoes 195 and 196 respectively, these inner and outer brake shoes 195 and 196 being pivoted at 198 to brackets 199. The inner and outer shoes 195 and 196 have parallel extending legs 201 through which rods 202 extend. Springs 203 are placed on the extending ends of the rods 202, which springs are for the purpose of constricting the shoes, thus causing them to engage the brake drums 183 of the roller 165. Inner and outer cams 204 and 206 are pivoted on pins 207 which extend from formations 208 provided by the housings 150. Each of the inner cams 204 is situated between the parallel legs 201 of the inner brake shoes 195, and each of the outer cams is situated between the parallel legs 201 of the outer brake shoes 196. Rods 209 pivot 221 to outer armsl 222 provided by the tensioning levers 214. A roller arm 224 is provided by each of the tensioning levers 214, this roller arm 224 having-a roller 225.

rotatably arrangedl at the extending end thereof. Springs 227 are provided for each of the tensioning levers 214 for resiliently` vholding them in upper pbsiti on substantially as shown by the central lever of Fig. 2.

The outer cam of the series of rollers directly below a lever 214 is attached therewith, 'whereas the inner cam of this series of rollers is attached with a preceding tensioning lever. The inner and outer cams are so arranged with respect to each other that when one cam is holding a brake in releasing position, the other cam is allowing the brake tol assume an engaging position. When a tensioning lever 214 is in the lower position, the outer cam associated therewith is in releasing position and thev inner cam associated therewith is in engaging position, that is, in such 'a position that the brake shoes are releasing or engaging the brake drums 183. When a tensioning lever is in upper position, the outer cam associated therewith is in engaging position and the inner cam associated therewith is in re' leasing position.

The iilm is wound over the series of rollers 189 to 194 inclusive, and the rollers 225 of the tensioning levers 214 as shown in Fig. 2, the film extendin as indicated by dotted lines 230 and traveling in a direction indicated by arrows 231. The ilm extends to the first series of rollers 194 and is wound around the spool portions of the rollers 165 and 180 as indicated by dotted lines 232 of Fig. 3. The iilm then extends upwardly and over a roller 225 ofthe first tensioning lever .214, from thence it is carried over the series of rollers 193, being wound thereon in the same manner as on the series 194. IThe film is then extended directl to the series 192, and from the series 192 the film extends over the roller 225 of a second tensioning lever 214, after which it is extended and .wound around the series 191. This method of winding is repeated throughout the complete series of rollers of the apparatus.

When the lm is at a normal tension, all

of the tensioning levers 214 are retained in such a position that none of the inner or outer brakes engage. This position is substantially half way between the positions of rinto the position shown. The inner brakel shoes of the series 189 are allowed to engage the brake drum 183 of the upper roller 165 of this series, and the outer brake shoes 196 of the series of rollers 191 are held from engagement with the drum 183 of the rollers 165 of this series. This action retards the exhausting of the film from the series of rollers 190. and the film will feed into this series 190 from the series 191 in such a manner as to return the tension of the film to normal. When the tension in 'the film reduces belowl normal, the levers 214 are allowed to swing in an upper position as indicated by the central lever 214 of Fig; 2, the lever being swung into this position by the springs 227. When a lever swings intothis position, the inner brake shoes 195 associated therewith are held from engagement with the drum 183 of the upper roller 165 of the series of rollers 191, and the outer brake shoes -196 of the upper roller 165 of the series of rollers 193 are permitted to engage,

thus retarding the rotation of this roller 165. As is obvious, this will retard the feeding of the film tothe series of rollers 192 with respect to the speed at which they are ex hausted from this series. This will gradually increase the tension in the film 'at this point and return it to normal condition.

Y A decrease in tension at any point affects all of the series of rollers preceding, and an increase in tension of the point will afi'ect all series of rollers following it in substantially the samemanner as in the first form of my invention. When any of the levers 214 move upwardly as into 'the position shown by the central lever 214, the outer brake shoes associated therewith will retard the rotation of` a roller therebelow, thus slowing the exhaust speed of the film from a .preceding roller. This consequently allows the preceding tensioning arm to swing upwardly and to retard the motion of a roller on which its outer brake operates. The effect on the consecutive preceding roller gradually reduces to nothing; thus the decrease in tension is compensated for. When the tension increases in the film at any point, the lever 214 in that vicinity is swung into the position indicated by the left hand lever in Fig. 1. This applies the inner brake associated therewith, reducing the speed of a rollerY associated. with this inner brake.

Consequently, the tension in the following series of rollers is increased and a lever 214 is swung down, these levers being consecutively swung until the increase in tension is compensated for and the lmis returned to normal tension.

I claim as my invention:

1. In a film apparatus, the combination of: pairs of upper and lower rollers having a film wound therearound; means for driving a roller of said pairs; brakes adapted to operate on rollers of certain of said pairs; and tensioning levers, said tensioning levers each being connected to two of said brakes, and said tensioning levers being operated by said film when the tension of said film varies so as to change the rotational speed of said rollers.

2. In a film apparatus, the combination of: pairs of upper and lower rollers having a film wound therearound; means for driving al roller of saidY pairs; brakes adapted to operate on rollers of alternate of said pairs; and tensioning levers, said tensioning levers each being connected to two of said brakes, `and said tensioning levers being operated by said film when the tension .of said film varies so as to change the rotational speed of said rollers.

3. In a film apparatus, the combination of: pairs of upper and lower rollers having a film wound therearound; means for driving a roller of said pairs; pairs rof lbrakes adapted to operate on rollers of certain of said pairs; and tensioning levers, said tensioning levers each being connected to two of said brakes of different pairs of brakes, and said tensioning levers being operated by said film when the tension of said film varies so as to change the rotational speed of said rollers.

4. In a film apparatus, the combination of: pairs of upper and lower rollers having a film wound therearound; means for driving aproller of said pairs; pairs of brakes adapted to operate on rollers of alternate of said pairs; and tensioning levers, said tensioning levers each being connected to two of said brakes of different pairs of brakes, and said tensioning levers being operated by said film when the tension of said film varies so as to change the rotational speed of said rollers.

'f 5. In a film apparatus, the combination of: pairs of upper and lower rollers having a film wound therearound; means for driving a roller of said pairs; inner brakes adapted to operate on rollers of certain of.

said pairs; outer brakes adapted to operate on the same rollers as said inner brakes; cams adapted to operate said inner and outer brakes; and tensioning means actuably connected to said cams of inner and outer brakes of successive rollers, and said tensioning means being o erated by said film when the tension of sai film varies in order to change the rate of rotation of said rollers.

6. In a film apparatus, the combination of: pairs of up er and lower rollers having a film Wound t erearound; means for driving a roller of said pairs; inner brakes adapted to operate on rollers of alternate of said pairs; .outer brakes adapted to operate on the same rollers as said inner brakes; cams adapted to operate said inner and outer 1P brakes; and tensioning levers actuably connected'to said cams of inner and outer brakes of successive rollers, and said tensioning levers being o erated byl said -film when the tension of sai lm varies in order to change the rate of rotation of said rollers.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 23rd day of February, 1926.

FRANK E. GARBUTT. 

